In some circumstances, it is desirable to manipulate an object without using any direct mechanical contact because direct mechanical contact may cause contamination of or damage to the object being manipulated or of objects that the manipulated object contacts. Some situations in which direct mechanical contact is not desirable include protein crystal growth, containerless materials processing and particulate filtering. Such situations are especially common in applications which exploit gravity levels that are substantially weaker than Earth's surface gravity.
While magnetic manipulation has been attempted, its application has been limited. One prior magnetic manipulation method is limited to manipulation of microscopic objects. This method requires coating the object with materials containing paramagnetic salts, that is, materials that make the object more strongly magnetic. These coatings are unacceptable in applications striving for high purity in the object to be manipulated. Another prior method requires that the medium surrounding the object be a paramagnetic fluid. Yet another method requires that the object be immersed in a ferrofluid. Still another method requires that the object be made of an electrically conducting substance. Another method requires the use of a special superconducting coil and associated apparatus. This method is costly and constrains the object to a size smaller than the bore of the superconducting coil. Still another method is limited to a particular material, namely pyrolytic graphite, which has a high magnetic susceptibility and is anisotropic.
Accordingly, it is an object of this invention to provide a method and system for diamagnetic manipulation that applies to both macroscopic and microscopic objects.
It is another object of this invention to provide a method and system for diamagnetic manipulation that does not require introducing impurities into the object being manipulated.
It is another object of this invention to provide a method and system for diamagnetic manipulation that does not require the surrounding medium to be a fluid. Additionally, if the surrounding medium is a fluid, the present invention does not require that the fluid be paramagnetic or a ferrofluid.
It is another object of this invention to provide a method and system for diamagnetic manipulation that does not limit application to electrically conductive objects.
It is another object of this invention to provide a method and system for diamagnetic manipulation that does not require the object to fit within the bore of a special superconducting coil.
It is another object of this invention to provide a method and system for diamagnetic manipulation that does not limit application to highly magnetically susceptible objects.
It is another object of this invention to provide a method and system for diamagnetic manipulation that applies to both isotropic and anisotropic objects, thereby eliminating the need to match the magnetic field orientation to the anisotropic nature of the object.